Calcium Pyrophosphate Dihydrate Disease (Pseudogout)

Clinical manifestations: CPPD can present with a wide range of clinical features

• Asymptomatic disease
•  Pseudo-RA: clinically very similar to RA, but joints do not demonstrate erosions
• Pseudo-OA: involves joints typically not affected by OA: MCP, shoulder, elbow, spine
• Pseudo-neruopathhic joint disease: joint degeneration resembling Charcot joint, with intact neurologic function
• Diffuse inflammatory response that mimics sepsis
•  Pseudogout:
  • Like gout, can be triggered by severe illness
  • Unlike gout, typically involves larger joints, such as the knee (50% of cases) and wrist
  • Crystal analysis yields weakly-positively birefringent rhomboid crystals, but these are notoriously difficult to detect, and thus sensitivity poor
  • Plain films can show chondrocalcinosis
  • Associated conditions:
    • Hemochromatosis
    • Hyperparathyroidism
    • Hypothyroidism
    • Hypomagnesemia
    • Hypophosphatemia
    • Familial hypocalciuric hypercalcemia

(Christopher Woo MD, 11/1/10)